1. Field of the Invention
The present invention is in the field of restraint systems used to provide a protective passenger environment.
2. Description of the Prior Art
Conventional seat belt systems combining a lap belt and an upper torso belt are well known. These three-point restraint systems are usually used with seats offering rigid support for the belts. As typically used in a vehicle, the three-point restraint system consists of single belt having its opposite ends mounted to a pair of retractors with a seat belt tongue connected to the belt intermediate to the belt ends. The tongue may be swung across the person and engaged with a buckle affixed to the seat thereby positioning one portion of the belt across the lap and another portion of the belt across the upper torso. In some systems, only one end of the belt is mounted to a retractor while the other end is anchored to the seat or vehicle. Seat belts are active restraint devices, requiring a passenger to actively engage the restraints for them to be effective.
School bus passenger seats usually do not employ active restraint safety devices, but instead rely on a passive restraint seat design. School bus passenger seats are built to specifications conforming to the safety standards set by the National Highway Traffic Safety Administration, DOT. These are codified as 49 C.F.R. Ch.V, xc2xa7571.222, Standard No. 222, and require that the seat back bend or deflect forward when a force is applied to the rear of the seat back. The code further specifies that 400W inch-pounds of energy must be absorbed within a maximum forward deflection of the seat back of 14 inches and 2800W inch-pounds be absorbed within a maximum rearward deflection of the seat back of 10 inches where W represents the number of seating positions for which the seat is designed. 49 C.F.R., Ch.V, xc2xa7571.222, S5.1.3-5.1.4. The code specifies a passive restraint system, and does not require any sort of active restraints, such as a two-point passenger restraining lap belt or a three-point passenger restraining lap belt and torso harness combination. Children riding the school bus are protected in head-on collisions by the seat back in front of them deflecting forward and absorbing some of their forward momentum.
Vehicles with deforming or deflecting seats provide special problems regarding the integration of active restraint seat belt systems. Passive restraint systems are designed to protect a passenger who has been thrown forward by having the impacted seat back deflect upon impact of the thrown passenger and absorb some of their momentum. In a school bus seat combining active and passive restraint systems, both of the restraint systems have to be able to perform their functions and the seat must still conform to the regulations set forth in 49 C.F.R.
In U.S. Pat. No. 5,746,476, there is disclosed an automotive seat having a tower frame associated with the harness to transmit impact loads to the floor. Despite the prior devices, there is still a need for increased protection for children riding the school bus in an emergency or crash situation. The addition of an active restraint system, such as a three-point lap belt and torso harness combination, provides enhanced passenger protection in a head-on crash as well as provides passenger protection in a broadside collision and/or roll situation. Disclosed herein is a three-point lap belt and torso harness passenger restraint system that is compatible with the pivoting and deflecting seats required by 49 C.F.R.
A further need is to provide a restraint system for a school bus seat that is operable to remove slack in the belt during rapid vehicle deceleration. The conventional method is to employ pretensioner devices connected to the belt which rapidly withdraw belt once a pyrotechnic charge fires upon sensed vehicle deceleration. Such pretensioner devices may be mounted beneath the seat. In the case of a school bus seat, the addition of a pretensioner device reduces storage space beneath the seat. In lieu of a pretensioner device, we have devised a device built into the seat to automatically takes up slack in the belt as the restrained passenger moves forward with the tower frame assembly during vehicle deceleration.
One embodiment of the present invention is a restraint apparatus for a passenger in a vehicle having a seat frame mountable to the vehicle. The frame includes a seat portion and a back portion. The back portion has a bottom end portion, and a top end portion with the back portion pivotable forwardly about the bottom end portion toward the seat portion upon crash force applied to the back portion. A retractor has a web extending therefrom through a web guide. The web has a chest portion and a lap portion positionable across a passenger located on the seat portion. The retractor has an unlocked position and a locked position. A first lock is mounted to the web and a second lock is mounted adjacent the seat portion and lockingly engageable with the first lock. A tower is mounted to the frame and movable with the back portion. A web tensioning arm is mounted to the frame and is moved by the tower to engage the web to take up slack in the web as the arm moves upon crash of the vehicle.
It is an object of the present invention to provide an active restraint system compatible with existing passive restraint school bus seats and the present Federal safety regulations.
A further object of the present invention is to provide an active restraint system for school bus passengers.
It addition, it is an object of the present invention to provide a device for removing or taking up slack in the restraint belt during vehicle deceleration.
Related objects and advantages of the present invention will be apparent from the following description.